Referring to FIG. 1, a miter saw typically has a base assembly 10, a table assembly 20 rotatably attached to the base assembly 10, a support housing 30 connected to the table assembly 20, and a saw assembly 40 pivotally connected to the support housing 30. The saw assembly 40 may include an arm 41 pivotally connected to support housing 30, an upper blade guard 42 connected to arm 41, a motor (not shown) supported by arm 41 and/or upper blade guard 42, a blade 43 driven by the motor, and a lower blade guard 44 pivotally attached to the upper blade guard.
A fence assembly 15 is typically attached to base assembly 10. With such construction, a user can place a work piece against fence assembly 15 and table assembly 20 for cutting. The user can make a miter cut by rotating table assembly 20 relative to base assembly 10.
If support housing 30 is pivotally attached to table assembly 20, the user can rotate support housing 30 relative to table assembly 20 and/or base assembly 10, tilting the blade 43 relative to the table assembly 20, thus changing the blade's bevel angle. A cut made with the blade 43 tilted at an angle (and perpendicular to the fence assembly 15) is known as a “bevel cut.” A cut made with the blade 43 set to both an angle relative to the fence assembly 15 (miter angle) and an angle relative to the base assembly 10 (bevel angle) is known as a “compound cut.”
Miter saws typically include a detent system 12 that allows the table assembly 20 and the blade 43 to be preset to specific angles relative to the fence assembly 15. A detent system 12 provides an accurate means to preset and reset the saw to make the most popular cuts. Such detent system 12 may include a detent plate 13 with detent recesses formed thereon. Alternatively, the detent recesses may be formed on base assembly 10. Such recesses can receive a spring-biased detent, fixing the position of table assembly 20 relative to the fence assembly 15. Persons skilled in the art are directed to US Published Application No. 2005/0284276, which is hereby fully incorporated by reference, for further information on such detent systems, operation thereof, and miter lock mechanisms.
If a user wants to preset the miter saw for an angle cut not provided by the detent system, the user would allow the spring-loaded detent to rest against the detent plate 13 and/or the base assembly 10 outside of the detent recesses and engage the miter lock mechanism. Due to the interaction between the spring-loaded detent and the detent recesses, however, the prior art arrangements do not allow for a fine adjustment that is near one of the predetermined detent positions.
Some solutions have been proposed to solve this problem. US Published Application No. 2004/0154448, for example, discloses a mechanism for adjusting the position of the detent engaging the recesses. However, such mechanism is difficult to adjust and to reset to the original position.
Similarly, US Published Application Nos. 2005/0284276, 2005/0262984 and 2006/0016310 disclose rack-and-pinion and/or worm drive mechanisms for adjusting the position of the table assembly relative to the base assembly. However such mechanisms are difficult to reset to the original position.